Son made mistake treating for ick

[jjstanley]

My son treated his saltwater tank with a copper ick medicine without isolating his fish. The tank contained live rock. Next day,fish in heaven. Does he need to empty tank and start all over?

 

[beth]

What do you plan on doing with that tank? If it was to be a reef tank, then yes, you will not only need to start over, but you will need to get new LR. If it is just FOWLR, then you might be able to revive the rock.
Try doing a major water change, and doing carbon filtration for a month, changing the carbon once a week.